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GEOHM C EARTH
SOIL RESISTIVITY TESTER |
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GEOHM C
Battery
Powered Earth Tester
measuring instrument for the measurement of soil resistivity resistance |
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GEOHM C Earth Resistivity
Tester.
GEOHM C Compact, handy, menu-driven soil
resistance, resistivity, earthing measuring instrument
for 3 and 4-wire connection with
continuous monitoring of interference voltage and earth electrode
and probe resistance with indication if allowable limit values are
exceeded.
Complete indication of all necessary values at a large dot matrix
display, or warning with 4 LEDs.
Easily comprehensible, simple operation with 4 keys
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Soil Earth resistance, resistivity, earthing
measuring instrument |
- Earth resistance
measurement in 5 ranges up to
50 kOhm - Voltage measurement
from 10 to 250 V
- Frequency
measurement from 45 to 200 Hz
- Battery monitoring
and self-test
- Integrated memory
with IrDA interface
- Factory calibration
certificate
- Extremely rugged,
two-component housing
- per VDE 0413 Part 5,
EN 61557-5
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Applications
The GEOHM C is a
compact instrument for the measurement of ground resistance in
electrical systems in accordance with:
DIN VDE 0100
Installation of power systems with nominal voltages of up to 1000 V
DIN VDE 0141 Grounding in AC systems with nominal voltages of
greater than 1 kV
DIN VDE 0800 Installation and operation of telecommunications
systems including data processing systems: equipotential bonding and
grounding
Testing of lightning
protection systems in accordance with DIN VDE 0185
The instrument is also capable of determining soil resistivity which
is essential in calculating
dimensions for grounding systems.
It can thus be taken advantage of for simple, geological surveys,
and for the planning of grounding systems.
Beyond this, ohmic resistance can be measured at both solid and
liquid conductors, as well as internal resistance at conductive
elements, as long as these are capacitance and induction-free.
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Special Functions
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Hold function: The
measurement value is frozen at the display after the measurement key
is released.
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Storage of measurement values to memory
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Data interface for the transmission of measurement values and
for software updates
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Convenient report generating software, can be expanded into a
comprehensive database
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Earthing resistance is
measured with the GEOHM C by means of the ammeter-voltmeter
test method.
The battery powered, potential-free constant power source (quartz
controlled square-wave generator) delivers constant current of up to
10 mA at a frequency of 128 Hz to the measuring ranges.
In the interest of safety, maximum test voltage at the terminals is
limited to 50 V with reference to earth.
Constant test current travels via terminal E through the earth
electrode whose resistance RE is to be measured, through the
auxiliary resistor RH and finally to terminal H. The voltage drop
which occurs due to earthing resistance RE, and which is measured at
terminals ES or E and S, is first fed first to an electronic filter
which is synchronous to the generator, and then to a synchronously
controlled rectifier in order to eliminate influences caused by
polarization voltages and stray alternating currents which are
present in the soil to the greatest possible extent.
The earthing resistance to be measured is proportional to the
voltage drop. It is displayed directly at the LCD in digital format.
Crucial operating conditions are continuously monitored for possible
errors.
The presence of interference voltage and values in excess of
allowable auxiliary earth conductor resistance at the external
current circuit are signaled by means of LEDs. Probe resistance at
the voltage circuit is measured each time a measurement is started.
If the allowable value is exceeded, the appropriate LED lights up.
Excessively low battery voltage and over-ranging are indicated at
the LCD.
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